Which thermal stability is better, lithium iron phosphate battery or ternary lithium ion battery?

1. Comparison of thermal stability of materials between lithium iron phosphate batteries and ternary lithium ion batteries. The phase transition temperatures of ternary lithium ion batteries from the lamellar phase to the spinel phase are 245℃, 235℃, 185℃ and 135℃, respectively. , The temperature range in which the spinel phase exists gradually decreases, indicating that the thermal stability of NCM gradually decreases with the increase of Ni content. More importantly, from NCM523 to NCM811, the thermal stability of the material shows a trend of sharp decline. With the phase transition of the material, a large amount of oxygen is released. It can be seen that NCM811 has the largest oxygen release, which is several times that of other materials. The current research shows that in the whole battery system, the NCM phase transition often occurs on the surface of the particles, and the released oxygen will exist in the form of highly active singlet oxygen 1O2. The latter reacts with the electrolyte to release a large amount of heat and also occur. A large amount of gas, which further deteriorates battery safety. Lithium iron phosphate batteries will have significant weight loss only when the temperature is at least higher than 230°C, which indicates that LFP has good thermal stability. As mentioned above, the good thermal stability of LFP with olivine structure originates from the phosphate group in its structure, and the Fe-PO bond is much stronger than the Ni-O, Co-O and Mn-O bonds in the layered structure NCM, so LFP has better thermal stability than NCM. 2. Comparison of full battery thermal stability between lithium iron phosphate battery and ternary lithium ion battery. When it is difficult to find the comparison between lithium iron phosphate battery and ternary lithium ion battery at the same time, we can only roughly look at a lot of the results of the test data. It is not difficult to see: (1) The thermal stability of the battery of the same system is closely related to the SOC. The higher the SOC, the worse the thermal stability of the battery; (2) Whether it is from the initial heat release temperature and the maximum heat release rate, In terms of maximum temperature and heat release time analysis, the LFP system battery has obvious thermal stability advantages over the NCA (NCM) system battery. (3) From the perspective of the material itself, LFP is obviously better in thermal stability than NCM and NCA; Statement: Some pictures and content of articles published on this site are from the Internet, if there is any infringement, please contact to delete the previous one: what caused it Does the 18650 lithium-ion battery charge?